Amino-bacterial cellulose（amino-BC） was prepared by chemical modification of bacterial cellulose（BC）.The adsorption characteristics and mechanism of amino-BC were studied.The results show that adsorption data can ...Amino-bacterial cellulose（amino-BC） was prepared by chemical modification of bacterial cellulose（BC）.The adsorption characteristics and mechanism of amino-BC were studied.The results show that adsorption data can be fitted well by Langmuir equation and the pseudo-second order kinetics,indicating that the adsorption of amino-BC would obey monolayer molecule adsorption and the main action was chemisorption.Meanwhile,the adsorption process was studied by the Elovich equation and the intra-particle diffusion model,indicating that the absorption characteristics of metal ions on amino-BC is controlled by both film diffusion and particle diffusion.The increase of reaction temperature will accelerate the adsorbing rate because of endothermic reaction.展开更多
The adsorption kinetics of polystyrene[1-butyl-3-methylimidazolium][bis(2,4,4-trimethylpentyl)phosphinate](PS[C_(4)mim][C272])towards V(V)in acidic leachate was explored under ultrasound.The effects of ultrasonic powe...The adsorption kinetics of polystyrene[1-butyl-3-methylimidazolium][bis(2,4,4-trimethylpentyl)phosphinate](PS[C_(4)mim][C272])towards V(V)in acidic leachate was explored under ultrasound.The effects of ultrasonic power and V(V)concentration on the adsorption performance of PS[C_(4)mim][C272]were investigated.The results showed that ultrasonic radiation significantly shortened the adsorption equilibrium time and improved the adsorption performance of PS[C_(4)mim][C272]compared with the conventional oscillation.At an ultrasonic power of 200 W,the equilibrium adsorption capacity of PS[C_(4)mim][C272]reached its maximum of 311.58 mg/g.The kinetic model fitting results showed that the adsorption process of PS[C_(4)mim][C272]strictly followed the pseudo-second-order kinetic model under ultrasound.Analysis using the shrinking core model and the Weber−Morris model showed that the adsorption process of PS[C_(4)mim][C272]was primarily controlled by intra-particle diffusion mechanism.The adsorption isotherm model study showed that the Langmuir isotherm model could effectively fit the adsorption process of PS[C_(4)mim][C272]under ultrasound.展开更多
Batch adsorption from aqueous solutions in a slightly basic medium of Methylene Blue, up to 2500 mg/L, onto synthetic magnesium silicate （Florisil） of three particle size ranges （mean diameters of 112, 200 and 425 ...Batch adsorption from aqueous solutions in a slightly basic medium of Methylene Blue, up to 2500 mg/L, onto synthetic magnesium silicate （Florisil） of three particle size ranges （mean diameters of 112, 200 and 425 μm） was compared to the corresponding adsorption onto activated carbon and Amberlite XAD-2. The best fit of the kinetic results was achieved by a pseudo second-order equation. The equilibrium data were found to be well represented by the Langmuir isotherm equation. Amberlite XAD-2, an unspecific adsorbent capable of adsorbing exclusively through a surface effect, exhibited a poor dye uptake, confirming that the adsorption mechanism on Florisil was due to electrostatic attraction and ion exchange. Moreover, the comparison between Florisil and the other adsorbents was performed on the basis of the evaluation of the surface area and pore volume occupied by the adsorbed dye.展开更多
A semi-empirical adsorption kinetic model was proposed with the time compensation method to describe the chemisorption of SO2 in flue gas by carbon adsorbents for flue gas purification.The change in adsorption capacit...A semi-empirical adsorption kinetic model was proposed with the time compensation method to describe the chemisorption of SO2 in flue gas by carbon adsorbents for flue gas purification.The change in adsorption capacity and adsorption rate with time at different water vapor concentrations and different SO2 concentrations was studied.The model was in good agreement with experimental data.The surface reaction was probably the rate controlling step in the early stage for SO2 adsorption by ZL50 activated carbon.The parameters m and n in the nth order adsorption kinetic model were related to the magnitude of the time compensation and adsorption driving force,respectively.The change of parameter n with water vapor concentrations and sulfur dioxide concentrations was studied and some physical implications were given.The sum of square errors was less than 1.0 and the average absolute percentage deviations ranged from 0.5 to 3.2.The kinetic model was compared with other models in the literature.展开更多
The adsorption behavior of D301 for molybdenum blue was investigated.The thermodynamics parameters in adsorption process were calculated and the adsorption kinetics was studied.The experimental results show that the a...The adsorption behavior of D301 for molybdenum blue was investigated.The thermodynamics parameters in adsorption process were calculated and the adsorption kinetics was studied.The experimental results show that the adsorption characteristic of D301 for molybdenum blue fits well with the Freundlich adsorption isotherm equation.In the adsorption process of D301 for molybdenum blue,both the enthalpy change ΔH and entropy change ΔS are positive,while the free energy change ΔG is negative when temperatures are in the range of 303-333 K.It is indicated that the adsorption is a spontaneous and endothermic process,and the elevated temperatures benefit to the adsorption.Kinetic studies show that the kinetic data are well described by double driving-force model,and the adsorption rate of molybdenum blue on D301 is controlled by the intraparticle diffusion during the adsorption process.The total kinetic equation is determined.展开更多
The practical application of lithium-sulfur(Li-S)batteries is hindered by the sluggish redox kinetics of sulfur,significant volume expansion,and the shuttle effect of lithium polysulfides(LiPSs).To address these chall...The practical application of lithium-sulfur(Li-S)batteries is hindered by the sluggish redox kinetics of sulfur,significant volume expansion,and the shuttle effect of lithium polysulfides(LiPSs).To address these challenges,this study utilizes hollow carbon spheres(HCS)as a matrix,incorporating a heterojunction of transition metal sulfides(CoS_(2)/MoS_(2))as the sulfur host.The HCS,with their ultrahigh specific surface area,effectively mitigate structural damage to the cathode caused by sulfur’s volume expansion during charge and discharge cycles.Meanwhile,the CoS_(2)/MoS_(2)heterojunction provides abundant chemical adsorption and reaction sites,which accelerate the redox kinetics of sulfur and alleviating the shuttle effect of LiPSs.Density functional theory(DFT)calculations reveal that the coupling effect at the CoS_(2)/MoS_(2)heterointerface significantly enhances charge transfer and adsorption interactions between CoS_(2)/MoS_(2)and LiPSs.Experimental results demonstrate that Li-S batteries with S/CoS_(2)/MoS_(2)@HCS composites as the cathode exhibit an exceptionally low capacity decay rate of only 0.023%per cycle after 1200 cycles at 2.0 C.Even with high sulfur loading(7.9 mg cm^(−2))and a low electrolyte-to-sulfur(E/S)ratio(6.0μL mg^(−1)),the battery achieves an outstanding areal capacity of 6.86 mA h cm^(−2).This study develops a highly efficient CoS_(2)/MoS_(2)heterojunction within HCS for the adsorption and conversion of LiPSs,providing valuable insights into the design of high-performance cathode materials for Li-S batteries.展开更多
Heteroatom doping has emerged as a powerful strategy to optimize the catalytic and adsorption abilities of electrocatalysts by regulating the electronic structure,thereby enabling the development of efficient electroc...Heteroatom doping has emerged as a powerful strategy to optimize the catalytic and adsorption abilities of electrocatalysts by regulating the electronic structure,thereby enabling the development of efficient electrocatalysts for lithium-sulfur(Li-S)batteries.However,the correlation between the properties of doped atoms and adsorptio n-catalytic ability,as well as the interconnection between adsorption strength and catalytic activity,remains underexplored.Herein,we employed halogen atoms(F,Cl,and Br)with different electronegativities to dope nickel phosphide(Ni_(2)P),aiming to modulate the adsorption properties toward lithium polysulfides(LiPSs).We systematically explored the relationship between the electronegativity of the doping atoms and the adsorption strength,followed by exploring the connection between adsorption and catalytic capabilities.Combined experimental and theoretical analyses reveal that doping halogen atoms effectively strengthens d-p orbital hybridization between Ni atoms and S atoms,thereby enhancing LiPSs anchoring and conversion.Specifically,the chemical adsorption capability is enhanced as the electronegativity of the doped atoms increases.Moreover,the catalytic activity presents a volcano-like trend with the enhancement of adsorption performance,wherein the activity initially increases and subsequently diminishes.Therefore,Cl-doped Ni_(2)P with moderate chemisorption ability exhibits optimal redox kinetics in bidirectional sulfur conversion.Consequently,the Li-S batteries with Cl-Ni_(2)P-separators deliver a high-rate capacity of 790 mAh g^(-1)at 5 C and achieve a remarkable areal capacity of 7.36 mAh cm^(-2)under practical conditions(sulfur loading:7.10 mg cm^(-2);electrolyte/sulfur(E/S)ratio:5μL mg^(-1)).This work uncovers the significance of achieving a balance between adsorption and catalytic capabilities,offering insights into designing efficient electrocatalysts for lithium-sulfur batteries.展开更多
Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge ...Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge the gap between supply and demand.In this concern,a new material called Si-6G PAMAMPPAAM dendrimers modified silica gel terminated with phenylphosphonic acid-amide moieties was developed and its ability to adsorb Nd(Ⅲ)and Er(Ⅲ)from the phosphoric acid solution was investigated.K inetics and isotherm of the uptake process were investigated to explo re the so rption characte ristics.The attained results show that both metal ions exhibit the same adsorption performance,and the uptake process is depicted as a chemisorption,monolayer,uniform,and homogeneous process.The equilibrium state is achieved within 120 min,and the maximum uptake capacity is 16.7 mg Nd(Ⅲ)/g,and 14.0 mg Er(Ⅲ)/g.Sorption thermodynamics is an endothermic,spontaneous,and feasible uptake process.Nitric acid(1.0 mol/L)is found to be efficient for adsorbing about 94.3%and 92.5%of neodymium(Ⅲ)and erbium(Ⅲ)respectively,and the prepared Si-6G PAMAM-PPAAM demonstrates excellent stability over five consecutive sorption/desorption cycles.Preliminary tests on commercial phosphoric acid demonstrate that Si-6G PAMAM-PPAAM retains its effective REEs uptake from a complex comm ercial phosph oric acid solution.展开更多
The indiscriminate use and disposal of ciprofloxacin(CIP)have led to its detection in water globally,which pose a huge risk to public health and water environment.Herein,(Zn-Al)LDHs modified 3D reduced graphene oxide ...The indiscriminate use and disposal of ciprofloxacin(CIP)have led to its detection in water globally,which pose a huge risk to public health and water environment.Herein,(Zn-Al)LDHs modified 3D reduced graphene oxide nanocomposite((Zn-Al)LDHs/3D-rGO)was synthesized through a feasible onepot hydrothermal method for CIP removal.The highly distributed(Zn-Al)LDHs flakes on the surface of 3D-rGO endow the resulted(Zn-Al)LDHs/3D-rGO with an excellent adsorption performance for CIP.The adsorption results showed that the adsorption process could be well interpreted by Temkin isothermal model and the pseudo second-order kinetics model.The maximal adsorption capacity of 20.01 mg·g^(-1)for CIP could be achieved under the optimal conditions optimized by response surface methodology(RSM).The inhibitory effect of co-existing ions on CIP adsorption were also discussed.The probable adsorption mechanism might be ascribed toπ-πinteractions,hydrogen bonding,electrostatic,and surface complexation.Regeneration tests showed that the obtained 3D porous material also possessed pronounced recyclability.The obtained(Zn-Al)LDHs/3D-rGO holds a great potential for removal of CIP from actual wastewater.展开更多
In this study,we investigated improving the performance of a layered double hydroxide(LDH)for the adsorption of As(III)and As(V)by controlling the morphology of LDH crystals.The LDH was synthesized via a simple coprec...In this study,we investigated improving the performance of a layered double hydroxide(LDH)for the adsorption of As(III)and As(V)by controlling the morphology of LDH crystals.The LDH was synthesized via a simple coprecipitation method using barely soluble MgO as a precursor and succinic acid(SA)as a morphological control agent.Doping the LDH crystals with carboxylate ions(RCOO−)derived from SA caused the crystals to develop in a radial direction.This changed the pore characteristics and increased the density of active surface sites.Subsequently,SA/MgFe-LDH showed excellent affinity for As(III)and As(V)with maximum sorption densities of 2.42 and 1.60 mmol/g,respectively.By comparison,the pristine MgFe-LDH had sorption capacities of 1.56 and 1.31 mmol/g for As(III)and As(V),respectively.The LDH was effective over a wide pH range for As(III)adsorption(pH 3-8.5)and As(V)adsorption(pH 3-6.5).Using a combination of spectroscopy and sorption modeling calculations,the main sorption mechanism of As(III)and As(V)on SA/MgFe-LDH was identified as inner-sphere complexation via ligand exchangewith hydroxyl group(-OH)and RCOO−.Specifically,bidentate As-Fe complexeswere proposed for both As(III)and As(V)uptake,with the magnitude of formation varying with the initial As concentration.Importantly,the As-laden adsorbent had satisfactory stability in simulated real landfill leachate.These findings demonstrate that SA/MgFe-LDH exhibits considerable potential for remediation of As-contaminated water.展开更多
In the present study we reported the feasibility of the Anethum graveolens as biosorbent to remove Pb(II) from aqueous solutions. Anethum graveolens was characterized by scanning electron microscopy and elemental anal...In the present study we reported the feasibility of the Anethum graveolens as biosorbent to remove Pb(II) from aqueous solutions. Anethum graveolens was characterized by scanning electron microscopy and elemental analysis. The ability of Anethum graveolens to adsorb Pb(II) was investigated by using batch adsorption procedure. The effects such as pH, contact time, adsorbate concentration and biosorbent dosage on the adsorption capacity were studied. The experimental data were analysed using various adsorption kinetic models viz., the pseudo-first and second-order equations, Bangham’s equation, intraparticle diffusion and Elovich models. Results show that the pseudo-second-order equation provides the best correlation for the biosorption process. The equilibrium nature of Pb(II) adsorption at 30℃ has been described by the Langmuir, Freundlich, Temkin and Redlich-Peterson isotherm models. The equilibrium data fit well on Langmuir isotherm. The monolayer adsorption capacity of Pb(II) onto Anethum graveolens as obtained from Langmuir isotherm at 30℃ was found to be 303 mg/g. This high adsorption capacity of Anethum graveolens places this biosorbent as one of the best adsorbents for removal of Pb(II) from aqueous effluents.展开更多
A complete study of adsorption processes will be less complete if the structure and dynamics of its different elements and how they interact is not well captured. Therefore, the extensive study of adsorption thermodyn...A complete study of adsorption processes will be less complete if the structure and dynamics of its different elements and how they interact is not well captured. Therefore, the extensive study of adsorption thermodynamics in conjunction with adsorption kinetics is inevitable. Measurable thermodynamic </span><span style="font-family:Verdana;">properties such as temperature equilibrium constant and their non-measurable</span><span style="font-family:Verdana;"> counterparts such as Gibbs free energy change, enthalpy, entropy etc. are very important design variables usually deployed for the evaluation and prediction of the mechanism of adsorption processes.展开更多
How to remove trace amount of sulfur in benzene is of significance,and deep desulfurization by Ni-containing absorbents is an efficient and promising method.In this paper,The Raney Ni/Al2 O3 adsorbent was prepared and...How to remove trace amount of sulfur in benzene is of significance,and deep desulfurization by Ni-containing absorbents is an efficient and promising method.In this paper,The Raney Ni/Al2 O3 adsorbent was prepared and its kinetic and thermodynamic characteristics on adsorptive desulfurization of benzene were studied.The results showed that Raney Ni/Al2 O3 adsorbent exhibited good adsorption performance.The equilibrium isotherms indicated that the adsorption of thiophene over the Raney Ni/Al2 O3 adsorbent complied with the Freundlich model.The results of adsorption kinetics studies showed that the pseudo-second-order kinetics equation was more advantageous than the pseudo-first-order kinetics equation in describing the adsorption kinetics of thiophene on Raney Ni/Al2 O3.The rate constant value(kp)was positively correlated with the temperature whereas the adsorption mass transfer process was mainly determined by the intraparticle and film diffusion.The adsorption thermodynamic analysis proved that△G^0<0,△H^0>0,and△S^0>0,implying that the adsorption was a spontaneous,entropy-increasing and endothermic process.展开更多
Ammonium adsorption and desorption properties by purple soils with dif- ferent pH were studied. The results showed that the adsorption and desorption amounts of NH4＋ by purple soils increased with the increase of NH4...Ammonium adsorption and desorption properties by purple soils with dif- ferent pH were studied. The results showed that the adsorption and desorption amounts of NH4＋ by purple soils increased with the increase of NH4＋ concentration, regardless of soil pH values; the largest adsorption and desorption amounts of NH4＋ by purple soil at pH 6.0 were 10.3 and 7.96 mg/g, respectively; the largest adsorp- tion and desorption amounts of NH4＋ by purple soil at pH 7.2 were 12.8 and 4.62 mg/g, respectively; the largest adsorption and desorption amounts of NH4＋ by purple soil at pH 8.0 were 13.5 and 2.23 mg/g, respectively. The isothermal adsorption ki- netics of NH4＋ by purple soils fits the Freundlich equation best （R〉0.95）. This study shows that the adsorption of NH4＋ by purple soils with different pH values is multi- molecular layer uneven surface adsorption.展开更多
The adsorption characteristics of Pb on sediments of the Dianshan Lake in Shanghai was studied. The results show that (1) the relationship between the amount q of apparent equilibrium adsorption and the equilibrium co...The adsorption characteristics of Pb on sediments of the Dianshan Lake in Shanghai was studied. The results show that (1) the relationship between the amount q of apparent equilibrium adsorption and the equilibrium concentration C conforms to the Freundlich isothermal adsorption equation; (2) the adsorption and desorption of Pb on sediments are not reversible, that is, adsorption/desorption of Pb exhibits hysteresis; (3) Pb adsorption behavior is initially fast, followed by a slow reaction, and the slow reaction conforms to a reversible first-order reaction; (4) by deducing the Pb adsorption kinetics, four kinetics parameters n,k 1,k 2,q (max) independent of C could be worked out; (5) the equilibrium parameter (K) and the free energy change (ΔG) could also be determined, and the negative values of free energy change (ΔG) indicate the spontaneous nature of the adsorption.展开更多
A general expression of the dynamic surface adsorption [Г（t）] on the expanding spherical surface was derived by solving the corresponding diffusion equation under different initial and boundary conditions. Differen...A general expression of the dynamic surface adsorption [Г（t）] on the expanding spherical surface was derived by solving the corresponding diffusion equation under different initial and boundary conditions. Different from the result of the still spherical surface, two factors （smaller than 1） appeared in the equation for the short time adsorption. Using the derived results, the adsorption kinetics of aqueous decanoyl-N-methylglucamine （Mega-10） solution was studied. In the short time region （t→0）, a good agreement of experimental results with the theory was reached and the adsorption was controlled by diffusion.展开更多
The large accumulation of coal gangue,a common industrial solid waste,causes severe environmental problems,and green development strategies are required to transform this waste into high-value-added products.In this s...The large accumulation of coal gangue,a common industrial solid waste,causes severe environmental problems,and green development strategies are required to transform this waste into high-value-added products.In this study,low-cost ceramsites adsorbents were prepared from waste gangue,silt coal,and peanut shells and applied to remove the organic dye methylene blue from wastewater.We investigated the microstructure of ceramsites and the effects of the sintering atmosphere,sintering temperature,and solution pH on their adsorption performance.The ceramsites sintered at 800℃under a nitrogen atmosphere exhibited the largest three-dimensional-interconnected hierarchical porous structure among the prepared ceramsites;further,it exhibited the highest methylene blue adsorption performance,with an adsorption capacity of 0.954 mg·g^(−1),adsorption efficiency of over 95%,and adsorption equilibrium time of 1 h at a solution pH of 9.The removal efficiency remained greater than 75%after five adsorption cycles.The adsorption kinetics data were analyzed using various models,including the pseudosecond-order kinetic model and Langmuir equation,and the adsorption was attributed to electrostatic interactions between the dyes and ceramsites,n-interactions,and hydrogen bonds.The prepared coal gangue ceramsites exhibited excellent adsorption capacities,removal rates,and cyclic stabilities,demonstrating their promising application prospects for the comprehensive utilization of solid waste and for wastewater treatment.展开更多
Mango peels,which constitute a significant proportion of urban waste,have been modified with phosphoric acid for use as a biosorbent in the removal of methylene blue from wastewater.The characterization of the obtaine...Mango peels,which constitute a significant proportion of urban waste,have been modified with phosphoric acid for use as a biosorbent in the removal of methylene blue from wastewater.The characterization of the obtained biosorbent showed that cellulose is the primary constituent followed by lignin and hemicellulose.The high water content and the low value of ash content indicate that the studied biosorbent is a porous material containing a low proportion of inorganic,inert,amorphous and unusable part for biosorbent production.The zero charge point(pHpzc)assessment showed that the overall surface charge of the biosorbent is negative and therefore plays a key role in the adsorption process.The adsorption of methylene blue by mango peels biosorbent is a two-step process:a rapid first step in which over 90%methylene blue is removed in less than 10 min followed by a slowdown of the adsorption rate when approaching the adsorption equilibrium.Among pseudo-first,pseudo-second order and intraparticle diffusion kinetics models studies,pseudo-second order was the best applicable to describe methylene blue adsorption,suggesting a two-step mechanism:the transfer of methylene blue molecules from the solution to the mango peels biosorbent surface,followed by the interaction between adsorbates and surface.The equilibrium adsorption data were analyzed by Langmuir,Freundlich and Temkin isotherms models.Among them,Langmuir was the best model to describe adsorption,indicating the existence of homogeneous distribution of adsorption sites on mango peels biosorbent surface and a mono-layer adsorption of methylene blue molecules.The low value of Temkin’s constant B relative to the interaction energy between methylene blue molecules and the surface of the biosorbent shows that the adsorption involved is a physisorption process.展开更多
This work was undertaken to investigate the behaviors and kinetics of toluene adsorption and desorption on activated carbons with varying pore structure. Five kinds of activated carbon from different raw materials wer...This work was undertaken to investigate the behaviors and kinetics of toluene adsorption and desorption on activated carbons with varying pore structure. Five kinds of activated carbon from different raw materials were selected. Adsorption isotherms and breakthrough curves for toluene were measured. Langmuir and Freundlich equations were fitted to the equilibrium data, and the Freundlich equation was more suitable for simulating toluene adsorption. The process consisted of monolayer, multilayer and partial active site adsorption types. The effect of the pore structure of the activated carbons on toluene adsorption capacity was investigated. The quasi-first-order model was more suitable for describing the process than the quasi-second-order model. The adsorption data was also modeled by the internal particle diffusion model and it was found that the adsorption process could be divided into three stages. In the external surface adsorption process, the rate depended on the specific surface area. During the particle diffusion stage, pore structure and volume were the main factors affecting adsorption rate. In the final equilibrium stage, the rate was determined by the ratio of meso-and macro-pores to total pore volume. The rate over the whole adsorption process was dominated by the toluene concentration. The desorption behavior of toluene on activated carbons was investigated,and the process was divided into heat and mass transfer parts corresponding to emission and diffusion mechanisms, respectively. Physical adsorption played the main role during the adsorption process.展开更多
Fly ash was used as a low-cost adsorbent for removing dissolved organic matter （DOM） in secondary effluent. Batch experiments were conducted under various adsorbent dosages, pH, contact time, temperatures and DOM fr...Fly ash was used as a low-cost adsorbent for removing dissolved organic matter （DOM） in secondary effluent. Batch experiments were conducted under various adsorbent dosages, pH, contact time, temperatures and DOM fractional characteristics. Under the optimum conditions of fly ash dosage of 15 g/L, temperature of 303 K and contact time of 180 min, a removal of 22.5% of the dissolved organic carbon （DOC）, 23.7% of UV-254, 25.9% of the trihalomethanes precursors in secondary effluent was obtained. The adsorption of DOM fractions onto fly ash all followed the pseudo second-order kinetic model, and the hydrophilic fraction adsorption by fly ash also fitted the intraparticle diffusion model quite well. Freundlich and Langmuir models were applicable to the fly ash adsorption and their constants were evaluated. The maximum adsorption capacities of the adsorptions revealed that fly ash was more effective in adsorbing hydrophilic fraction than the acidic fractions. Structure changes of the DOM fractions after fly ash adsorption were also characterized via spectrum analyzing. Those mechanisms presented critical step toward improved efficiencies of fly ash adsorption via further surface-modification.展开更多
基金Project (20130206059G X) supported by Science and Technology Key Project of Jilin Province,ChinaProject (20101553) supported by the Natural Science Foundation of Jilin Province,China+1 种基金Project (BSJXM-201226) supported by Doctor Science Research Starting Projects of Northeast Dianli University,ChinaProject (2013) supported by the 12th Five-Year Enhancing Innovation Projects of Northeast Dianli University,China
文摘Amino-bacterial cellulose（amino-BC） was prepared by chemical modification of bacterial cellulose（BC）.The adsorption characteristics and mechanism of amino-BC were studied.The results show that adsorption data can be fitted well by Langmuir equation and the pseudo-second order kinetics,indicating that the adsorption of amino-BC would obey monolayer molecule adsorption and the main action was chemisorption.Meanwhile,the adsorption process was studied by the Elovich equation and the intra-particle diffusion model,indicating that the absorption characteristics of metal ions on amino-BC is controlled by both film diffusion and particle diffusion.The increase of reaction temperature will accelerate the adsorbing rate because of endothermic reaction.
基金financially supported by the National Natural Science Foundation of China(No.52074204)Key R&D Program of Zhejiang Province,China(No.2022C03061)。
文摘The adsorption kinetics of polystyrene[1-butyl-3-methylimidazolium][bis(2,4,4-trimethylpentyl)phosphinate](PS[C_(4)mim][C272])towards V(V)in acidic leachate was explored under ultrasound.The effects of ultrasonic power and V(V)concentration on the adsorption performance of PS[C_(4)mim][C272]were investigated.The results showed that ultrasonic radiation significantly shortened the adsorption equilibrium time and improved the adsorption performance of PS[C_(4)mim][C272]compared with the conventional oscillation.At an ultrasonic power of 200 W,the equilibrium adsorption capacity of PS[C_(4)mim][C272]reached its maximum of 311.58 mg/g.The kinetic model fitting results showed that the adsorption process of PS[C_(4)mim][C272]strictly followed the pseudo-second-order kinetic model under ultrasound.Analysis using the shrinking core model and the Weber−Morris model showed that the adsorption process of PS[C_(4)mim][C272]was primarily controlled by intra-particle diffusion mechanism.The adsorption isotherm model study showed that the Langmuir isotherm model could effectively fit the adsorption process of PS[C_(4)mim][C272]under ultrasound.
文摘Batch adsorption from aqueous solutions in a slightly basic medium of Methylene Blue, up to 2500 mg/L, onto synthetic magnesium silicate （Florisil） of three particle size ranges （mean diameters of 112, 200 and 425 μm） was compared to the corresponding adsorption onto activated carbon and Amberlite XAD-2. The best fit of the kinetic results was achieved by a pseudo second-order equation. The equilibrium data were found to be well represented by the Langmuir isotherm equation. Amberlite XAD-2, an unspecific adsorbent capable of adsorbing exclusively through a surface effect, exhibited a poor dye uptake, confirming that the adsorption mechanism on Florisil was due to electrostatic attraction and ion exchange. Moreover, the comparison between Florisil and the other adsorbents was performed on the basis of the evaluation of the surface area and pore volume occupied by the adsorbed dye.
文摘A semi-empirical adsorption kinetic model was proposed with the time compensation method to describe the chemisorption of SO2 in flue gas by carbon adsorbents for flue gas purification.The change in adsorption capacity and adsorption rate with time at different water vapor concentrations and different SO2 concentrations was studied.The model was in good agreement with experimental data.The surface reaction was probably the rate controlling step in the early stage for SO2 adsorption by ZL50 activated carbon.The parameters m and n in the nth order adsorption kinetic model were related to the magnitude of the time compensation and adsorption driving force,respectively.The change of parameter n with water vapor concentrations and sulfur dioxide concentrations was studied and some physical implications were given.The sum of square errors was less than 1.0 and the average absolute percentage deviations ranged from 0.5 to 3.2.The kinetic model was compared with other models in the literature.
基金Project(2007AA06Z129) supported by the High-tech Research and Development Program of China
文摘The adsorption behavior of D301 for molybdenum blue was investigated.The thermodynamics parameters in adsorption process were calculated and the adsorption kinetics was studied.The experimental results show that the adsorption characteristic of D301 for molybdenum blue fits well with the Freundlich adsorption isotherm equation.In the adsorption process of D301 for molybdenum blue,both the enthalpy change ΔH and entropy change ΔS are positive,while the free energy change ΔG is negative when temperatures are in the range of 303-333 K.It is indicated that the adsorption is a spontaneous and endothermic process,and the elevated temperatures benefit to the adsorption.Kinetic studies show that the kinetic data are well described by double driving-force model,and the adsorption rate of molybdenum blue on D301 is controlled by the intraparticle diffusion during the adsorption process.The total kinetic equation is determined.
基金supported in part by the Institute for Advanced Study of Central South University and the High Performance Computing Center of Central South University。
文摘The practical application of lithium-sulfur(Li-S)batteries is hindered by the sluggish redox kinetics of sulfur,significant volume expansion,and the shuttle effect of lithium polysulfides(LiPSs).To address these challenges,this study utilizes hollow carbon spheres(HCS)as a matrix,incorporating a heterojunction of transition metal sulfides(CoS_(2)/MoS_(2))as the sulfur host.The HCS,with their ultrahigh specific surface area,effectively mitigate structural damage to the cathode caused by sulfur’s volume expansion during charge and discharge cycles.Meanwhile,the CoS_(2)/MoS_(2)heterojunction provides abundant chemical adsorption and reaction sites,which accelerate the redox kinetics of sulfur and alleviating the shuttle effect of LiPSs.Density functional theory(DFT)calculations reveal that the coupling effect at the CoS_(2)/MoS_(2)heterointerface significantly enhances charge transfer and adsorption interactions between CoS_(2)/MoS_(2)and LiPSs.Experimental results demonstrate that Li-S batteries with S/CoS_(2)/MoS_(2)@HCS composites as the cathode exhibit an exceptionally low capacity decay rate of only 0.023%per cycle after 1200 cycles at 2.0 C.Even with high sulfur loading(7.9 mg cm^(−2))and a low electrolyte-to-sulfur(E/S)ratio(6.0μL mg^(−1)),the battery achieves an outstanding areal capacity of 6.86 mA h cm^(−2).This study develops a highly efficient CoS_(2)/MoS_(2)heterojunction within HCS for the adsorption and conversion of LiPSs,providing valuable insights into the design of high-performance cathode materials for Li-S batteries.
基金supported by the Beijing Institute of Technology Research Fund Program for Young Scholars and 21C Innovation Laboratory Contemporary Amperex Technology Co.,Limited,Ninde,352100,China(21C-OP-202314)。
文摘Heteroatom doping has emerged as a powerful strategy to optimize the catalytic and adsorption abilities of electrocatalysts by regulating the electronic structure,thereby enabling the development of efficient electrocatalysts for lithium-sulfur(Li-S)batteries.However,the correlation between the properties of doped atoms and adsorptio n-catalytic ability,as well as the interconnection between adsorption strength and catalytic activity,remains underexplored.Herein,we employed halogen atoms(F,Cl,and Br)with different electronegativities to dope nickel phosphide(Ni_(2)P),aiming to modulate the adsorption properties toward lithium polysulfides(LiPSs).We systematically explored the relationship between the electronegativity of the doping atoms and the adsorption strength,followed by exploring the connection between adsorption and catalytic capabilities.Combined experimental and theoretical analyses reveal that doping halogen atoms effectively strengthens d-p orbital hybridization between Ni atoms and S atoms,thereby enhancing LiPSs anchoring and conversion.Specifically,the chemical adsorption capability is enhanced as the electronegativity of the doped atoms increases.Moreover,the catalytic activity presents a volcano-like trend with the enhancement of adsorption performance,wherein the activity initially increases and subsequently diminishes.Therefore,Cl-doped Ni_(2)P with moderate chemisorption ability exhibits optimal redox kinetics in bidirectional sulfur conversion.Consequently,the Li-S batteries with Cl-Ni_(2)P-separators deliver a high-rate capacity of 790 mAh g^(-1)at 5 C and achieve a remarkable areal capacity of 7.36 mAh cm^(-2)under practical conditions(sulfur loading:7.10 mg cm^(-2);electrolyte/sulfur(E/S)ratio:5μL mg^(-1)).This work uncovers the significance of achieving a balance between adsorption and catalytic capabilities,offering insights into designing efficient electrocatalysts for lithium-sulfur batteries.
文摘Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge the gap between supply and demand.In this concern,a new material called Si-6G PAMAMPPAAM dendrimers modified silica gel terminated with phenylphosphonic acid-amide moieties was developed and its ability to adsorb Nd(Ⅲ)and Er(Ⅲ)from the phosphoric acid solution was investigated.K inetics and isotherm of the uptake process were investigated to explo re the so rption characte ristics.The attained results show that both metal ions exhibit the same adsorption performance,and the uptake process is depicted as a chemisorption,monolayer,uniform,and homogeneous process.The equilibrium state is achieved within 120 min,and the maximum uptake capacity is 16.7 mg Nd(Ⅲ)/g,and 14.0 mg Er(Ⅲ)/g.Sorption thermodynamics is an endothermic,spontaneous,and feasible uptake process.Nitric acid(1.0 mol/L)is found to be efficient for adsorbing about 94.3%and 92.5%of neodymium(Ⅲ)and erbium(Ⅲ)respectively,and the prepared Si-6G PAMAM-PPAAM demonstrates excellent stability over five consecutive sorption/desorption cycles.Preliminary tests on commercial phosphoric acid demonstrate that Si-6G PAMAM-PPAAM retains its effective REEs uptake from a complex comm ercial phosph oric acid solution.
基金support from Basic research project of Education Department of Liaoning Province(LJKZ0256)Special Fund for Basic Scientific Research of Liaoning Province(LJKZSYLUGX027).
文摘The indiscriminate use and disposal of ciprofloxacin(CIP)have led to its detection in water globally,which pose a huge risk to public health and water environment.Herein,(Zn-Al)LDHs modified 3D reduced graphene oxide nanocomposite((Zn-Al)LDHs/3D-rGO)was synthesized through a feasible onepot hydrothermal method for CIP removal.The highly distributed(Zn-Al)LDHs flakes on the surface of 3D-rGO endow the resulted(Zn-Al)LDHs/3D-rGO with an excellent adsorption performance for CIP.The adsorption results showed that the adsorption process could be well interpreted by Temkin isothermal model and the pseudo second-order kinetics model.The maximal adsorption capacity of 20.01 mg·g^(-1)for CIP could be achieved under the optimal conditions optimized by response surface methodology(RSM).The inhibitory effect of co-existing ions on CIP adsorption were also discussed.The probable adsorption mechanism might be ascribed toπ-πinteractions,hydrogen bonding,electrostatic,and surface complexation.Regeneration tests showed that the obtained 3D porous material also possessed pronounced recyclability.The obtained(Zn-Al)LDHs/3D-rGO holds a great potential for removal of CIP from actual wastewater.
文摘In this study,we investigated improving the performance of a layered double hydroxide(LDH)for the adsorption of As(III)and As(V)by controlling the morphology of LDH crystals.The LDH was synthesized via a simple coprecipitation method using barely soluble MgO as a precursor and succinic acid(SA)as a morphological control agent.Doping the LDH crystals with carboxylate ions(RCOO−)derived from SA caused the crystals to develop in a radial direction.This changed the pore characteristics and increased the density of active surface sites.Subsequently,SA/MgFe-LDH showed excellent affinity for As(III)and As(V)with maximum sorption densities of 2.42 and 1.60 mmol/g,respectively.By comparison,the pristine MgFe-LDH had sorption capacities of 1.56 and 1.31 mmol/g for As(III)and As(V),respectively.The LDH was effective over a wide pH range for As(III)adsorption(pH 3-8.5)and As(V)adsorption(pH 3-6.5).Using a combination of spectroscopy and sorption modeling calculations,the main sorption mechanism of As(III)and As(V)on SA/MgFe-LDH was identified as inner-sphere complexation via ligand exchangewith hydroxyl group(-OH)and RCOO−.Specifically,bidentate As-Fe complexeswere proposed for both As(III)and As(V)uptake,with the magnitude of formation varying with the initial As concentration.Importantly,the As-laden adsorbent had satisfactory stability in simulated real landfill leachate.These findings demonstrate that SA/MgFe-LDH exhibits considerable potential for remediation of As-contaminated water.
文摘In the present study we reported the feasibility of the Anethum graveolens as biosorbent to remove Pb(II) from aqueous solutions. Anethum graveolens was characterized by scanning electron microscopy and elemental analysis. The ability of Anethum graveolens to adsorb Pb(II) was investigated by using batch adsorption procedure. The effects such as pH, contact time, adsorbate concentration and biosorbent dosage on the adsorption capacity were studied. The experimental data were analysed using various adsorption kinetic models viz., the pseudo-first and second-order equations, Bangham’s equation, intraparticle diffusion and Elovich models. Results show that the pseudo-second-order equation provides the best correlation for the biosorption process. The equilibrium nature of Pb(II) adsorption at 30℃ has been described by the Langmuir, Freundlich, Temkin and Redlich-Peterson isotherm models. The equilibrium data fit well on Langmuir isotherm. The monolayer adsorption capacity of Pb(II) onto Anethum graveolens as obtained from Langmuir isotherm at 30℃ was found to be 303 mg/g. This high adsorption capacity of Anethum graveolens places this biosorbent as one of the best adsorbents for removal of Pb(II) from aqueous effluents.
文摘A complete study of adsorption processes will be less complete if the structure and dynamics of its different elements and how they interact is not well captured. Therefore, the extensive study of adsorption thermodynamics in conjunction with adsorption kinetics is inevitable. Measurable thermodynamic </span><span style="font-family:Verdana;">properties such as temperature equilibrium constant and their non-measurable</span><span style="font-family:Verdana;"> counterparts such as Gibbs free energy change, enthalpy, entropy etc. are very important design variables usually deployed for the evaluation and prediction of the mechanism of adsorption processes.
基金financially supported by the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions(CIT&TCD 20130325)the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beijing Municipality(IDHT20180508)。
文摘How to remove trace amount of sulfur in benzene is of significance,and deep desulfurization by Ni-containing absorbents is an efficient and promising method.In this paper,The Raney Ni/Al2 O3 adsorbent was prepared and its kinetic and thermodynamic characteristics on adsorptive desulfurization of benzene were studied.The results showed that Raney Ni/Al2 O3 adsorbent exhibited good adsorption performance.The equilibrium isotherms indicated that the adsorption of thiophene over the Raney Ni/Al2 O3 adsorbent complied with the Freundlich model.The results of adsorption kinetics studies showed that the pseudo-second-order kinetics equation was more advantageous than the pseudo-first-order kinetics equation in describing the adsorption kinetics of thiophene on Raney Ni/Al2 O3.The rate constant value(kp)was positively correlated with the temperature whereas the adsorption mass transfer process was mainly determined by the intraparticle and film diffusion.The adsorption thermodynamic analysis proved that△G^0<0,△H^0>0,and△S^0>0,implying that the adsorption was a spontaneous,entropy-increasing and endothermic process.
基金Supported by National Natural Science Foundation of China(41271267)National Key Technology Research and Development Program(2013BAJ11B03)Special Scientific Research Fund of Environment Friendly Public Welfare Profession of China(2013467036)~~
文摘Ammonium adsorption and desorption properties by purple soils with dif- ferent pH were studied. The results showed that the adsorption and desorption amounts of NH4＋ by purple soils increased with the increase of NH4＋ concentration, regardless of soil pH values; the largest adsorption and desorption amounts of NH4＋ by purple soil at pH 6.0 were 10.3 and 7.96 mg/g, respectively; the largest adsorp- tion and desorption amounts of NH4＋ by purple soil at pH 7.2 were 12.8 and 4.62 mg/g, respectively; the largest adsorption and desorption amounts of NH4＋ by purple soil at pH 8.0 were 13.5 and 2.23 mg/g, respectively. The isothermal adsorption ki- netics of NH4＋ by purple soils fits the Freundlich equation best （R〉0.95）. This study shows that the adsorption of NH4＋ by purple soils with different pH values is multi- molecular layer uneven surface adsorption.
文摘The adsorption characteristics of Pb on sediments of the Dianshan Lake in Shanghai was studied. The results show that (1) the relationship between the amount q of apparent equilibrium adsorption and the equilibrium concentration C conforms to the Freundlich isothermal adsorption equation; (2) the adsorption and desorption of Pb on sediments are not reversible, that is, adsorption/desorption of Pb exhibits hysteresis; (3) Pb adsorption behavior is initially fast, followed by a slow reaction, and the slow reaction conforms to a reversible first-order reaction; (4) by deducing the Pb adsorption kinetics, four kinetics parameters n,k 1,k 2,q (max) independent of C could be worked out; (5) the equilibrium parameter (K) and the free energy change (ΔG) could also be determined, and the negative values of free energy change (ΔG) indicate the spontaneous nature of the adsorption.
基金Supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars (D4200111).
文摘A general expression of the dynamic surface adsorption [Г（t）] on the expanding spherical surface was derived by solving the corresponding diffusion equation under different initial and boundary conditions. Different from the result of the still spherical surface, two factors （smaller than 1） appeared in the equation for the short time adsorption. Using the derived results, the adsorption kinetics of aqueous decanoyl-N-methylglucamine （Mega-10） solution was studied. In the short time region （t→0）, a good agreement of experimental results with the theory was reached and the adsorption was controlled by diffusion.
基金supported by the Natural Science Foundation of China under Grant(No.52172099)the Provincial Joint Fund of Shaanxi(2021JLM-28).
文摘The large accumulation of coal gangue,a common industrial solid waste,causes severe environmental problems,and green development strategies are required to transform this waste into high-value-added products.In this study,low-cost ceramsites adsorbents were prepared from waste gangue,silt coal,and peanut shells and applied to remove the organic dye methylene blue from wastewater.We investigated the microstructure of ceramsites and the effects of the sintering atmosphere,sintering temperature,and solution pH on their adsorption performance.The ceramsites sintered at 800℃under a nitrogen atmosphere exhibited the largest three-dimensional-interconnected hierarchical porous structure among the prepared ceramsites;further,it exhibited the highest methylene blue adsorption performance,with an adsorption capacity of 0.954 mg·g^(−1),adsorption efficiency of over 95%,and adsorption equilibrium time of 1 h at a solution pH of 9.The removal efficiency remained greater than 75%after five adsorption cycles.The adsorption kinetics data were analyzed using various models,including the pseudosecond-order kinetic model and Langmuir equation,and the adsorption was attributed to electrostatic interactions between the dyes and ceramsites,n-interactions,and hydrogen bonds.The prepared coal gangue ceramsites exhibited excellent adsorption capacities,removal rates,and cyclic stabilities,demonstrating their promising application prospects for the comprehensive utilization of solid waste and for wastewater treatment.
文摘Mango peels,which constitute a significant proportion of urban waste,have been modified with phosphoric acid for use as a biosorbent in the removal of methylene blue from wastewater.The characterization of the obtained biosorbent showed that cellulose is the primary constituent followed by lignin and hemicellulose.The high water content and the low value of ash content indicate that the studied biosorbent is a porous material containing a low proportion of inorganic,inert,amorphous and unusable part for biosorbent production.The zero charge point(pHpzc)assessment showed that the overall surface charge of the biosorbent is negative and therefore plays a key role in the adsorption process.The adsorption of methylene blue by mango peels biosorbent is a two-step process:a rapid first step in which over 90%methylene blue is removed in less than 10 min followed by a slowdown of the adsorption rate when approaching the adsorption equilibrium.Among pseudo-first,pseudo-second order and intraparticle diffusion kinetics models studies,pseudo-second order was the best applicable to describe methylene blue adsorption,suggesting a two-step mechanism:the transfer of methylene blue molecules from the solution to the mango peels biosorbent surface,followed by the interaction between adsorbates and surface.The equilibrium adsorption data were analyzed by Langmuir,Freundlich and Temkin isotherms models.Among them,Langmuir was the best model to describe adsorption,indicating the existence of homogeneous distribution of adsorption sites on mango peels biosorbent surface and a mono-layer adsorption of methylene blue molecules.The low value of Temkin’s constant B relative to the interaction energy between methylene blue molecules and the surface of the biosorbent shows that the adsorption involved is a physisorption process.
基金supported by the Program for New Century Excellent Talents in University(NCET-12-0776)the National Natural Science Foundation of China(21507004)the Fundamental Research Funds for the Central Universities(FRF-TP-15-046A1)
文摘This work was undertaken to investigate the behaviors and kinetics of toluene adsorption and desorption on activated carbons with varying pore structure. Five kinds of activated carbon from different raw materials were selected. Adsorption isotherms and breakthrough curves for toluene were measured. Langmuir and Freundlich equations were fitted to the equilibrium data, and the Freundlich equation was more suitable for simulating toluene adsorption. The process consisted of monolayer, multilayer and partial active site adsorption types. The effect of the pore structure of the activated carbons on toluene adsorption capacity was investigated. The quasi-first-order model was more suitable for describing the process than the quasi-second-order model. The adsorption data was also modeled by the internal particle diffusion model and it was found that the adsorption process could be divided into three stages. In the external surface adsorption process, the rate depended on the specific surface area. During the particle diffusion stage, pore structure and volume were the main factors affecting adsorption rate. In the final equilibrium stage, the rate was determined by the ratio of meso-and macro-pores to total pore volume. The rate over the whole adsorption process was dominated by the toluene concentration. The desorption behavior of toluene on activated carbons was investigated,and the process was divided into heat and mass transfer parts corresponding to emission and diffusion mechanisms, respectively. Physical adsorption played the main role during the adsorption process.
基金supported by the National Nature Science Foundation of China (National Creative Research Groups)(No. 50821002)the Key Scientific and Technological Project of National Water Pollution Control and Management (No. 2009ZX07317-008)the Scientific and Technological Innovation Research Fund of Harbin (No.2010RFQXN111)
文摘Fly ash was used as a low-cost adsorbent for removing dissolved organic matter （DOM） in secondary effluent. Batch experiments were conducted under various adsorbent dosages, pH, contact time, temperatures and DOM fractional characteristics. Under the optimum conditions of fly ash dosage of 15 g/L, temperature of 303 K and contact time of 180 min, a removal of 22.5% of the dissolved organic carbon （DOC）, 23.7% of UV-254, 25.9% of the trihalomethanes precursors in secondary effluent was obtained. The adsorption of DOM fractions onto fly ash all followed the pseudo second-order kinetic model, and the hydrophilic fraction adsorption by fly ash also fitted the intraparticle diffusion model quite well. Freundlich and Langmuir models were applicable to the fly ash adsorption and their constants were evaluated. The maximum adsorption capacities of the adsorptions revealed that fly ash was more effective in adsorbing hydrophilic fraction than the acidic fractions. Structure changes of the DOM fractions after fly ash adsorption were also characterized via spectrum analyzing. Those mechanisms presented critical step toward improved efficiencies of fly ash adsorption via further surface-modification.
